The Highway-Addressable Remote Transducer (HART) communications protocol is an implementation of a half duplex digital industrial communication protocol. HART communication can be implemented, as an example, for real-time distributed control. HART communications can be implemented in two modes: peer-to-peer mode, in which analog and digital signals can be transmitted on a process current loop, and a multi-drop mode which implements digital communication only. For example, in the peer-to-peer mode, digital communication signals can be modulated onto a 4-20 milliamp (mA) analog current loop for communication between two HART devices.